This application is generally related to applicant's U.S. Pat. No. 4,673,608 entitled Book Panel Construction.
As is known in the book panel and bookbinding industry, hardcover books 10 generally have a solid front panel 20 and a solid rear panel 21 with a flexible middle binding section 25 as shown in FIG. 1.
The FIG. 2 prior art drawing illustrates the current construction of padded book panels.
Typically, as shown in FIG. 2, the prior art padded book panels consist of a lower paperboard layer 31 to which is adhesively secured at 35 a foamed plastic compound 38. A vinyl covering layer 39 is also normally added.
By reason of the soft foamed plastic layer 38, when a pressure force P is applied to the panel, i.e. by manually touching it, the panel yields and has a padded high quality feel to the touch.
While such prior art structures have been widely used in the book panel industry, it has been realized by the present inventor that a more economically advantageous structure may be manufactured which produces the same padded effect of prior art systems.
The prior art padded panels of FIG. 2 are typically quite costly to manufacture.
The adhesive joint 35 between the paperboard layer 31 and the foamed soft plastic layer 35 is typically difficult to achieve.
Further, the use of soft foamed plastics compounds produces an industrial hazard resulting from the multiple chemicals and binders required in the production thereof.
Accordingly, it is an object of the present invention to produce a padded book panel structure which is fabricated entirely of paperboard materials.
It is a further object of the invention to utilize economical chipboard materials where possible in the structure.
It is also an object of the present invention to combine flat chipboard layers with undulating layers of longer fiber length paperboard positioned therebetween.
It is also an object to provide that the book panel be subjected to roller pressure treating such that an upper undulating layer is crushed to provide a plush or padded feel to the panel.
It is a further object to provide that a lower undulating layer remain in its substantially uncrushed position to add rigidity to the structure.
Further objects and advantages of the present invention will become apparent as the following description proceeds, and the features of novelty characterizing the invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.